Chapter 2 Constant Voltage Tests
RIGOL
DP1308A Performance Verification Manual
2-7
CV Ripple and Noise
Periodic and random deviations (PARD) in the output combine to produce a residual
AC voltage superimposed on the DC output voltage when the power supply is
operating in CV mode. This residual voltage, namely the ripple and noise (usually,
ripple is periodic offset while noise is random offset) is specified as the RMS or
peak-to-peak noise.
1.
Turn off DP1308A. Connect DP1308A, AC source, resistive load (1.2Ω for +6V/5A
channel; 25Ω for +25V/1A and -25V/1A channels) and oscilloscope according to
Figure 2-1 (connect the positive terminal of the oscilloscope probe to the positive
terminal of the output channel of the power supply and the ground terminal to
the negative terminal. Note: you’d better use ground spring as ground wire so as
to minimize the current coupling area between the probe tip and the ground wire
and to minimize the space radiation interference).
Note:
Do not connect the negative terminal of the output terminal to the shielding
ground; otherwise, a ground loop would be formed. The A connection in
Figure 2-3 forms a ground loop while B connection is correct.
Use resistive load instead of electronic load to avoid affecting the noise
measurement of the power supply by the electronic load noise.
A. Wrong Connection
Power Supply under Test
Oscilloscope
Vertical Input
